
class Base {
    private int x;
    private int y;

    public Base(int x, int y) {
        this.x = x;
        this.y = y;
    }
    public int getX() {
        return x;
    }
    public int getY() {
        return y;
    }

    public int calculate() {
        return x * y;
    }
}

class Sub extends Base {
    public Sub(int x, int y) {
        super(x, y);
    }
    public int calculate() {
        return getX() / getY();
    }
}
public class Test {
    public static void main(String[] args) {
        Sub sub = new Sub(20, 10);
        int differance = sub.calculate();
        System.out.println(differance);
    }
}
